G'day, Resolving the quandary. Matt's boat runs at 4 knots on 18 watts. Its also possible that his calculations included just the power to move the boat, not the power to raise the paddle in which case the total power to propel the boat might be 18W plus 8W to raise the paddle ie. 26 Watts. Its also possible that some of the power used in raising the paddle blade is returned and contributes to moving the boat by: positioning the blade, as a counterweight to the opposing blade and as a propulsion force as the blade falls through the water. Lets say a net value of 50% power returned. If that's the case then the net power to raise the paddle after subtracting returned useful power becomes 4W, and the total power becomes 26W minus 4W returned power so we have a ratio of 4W net average power to raise the blade and 22W total average paddling energy. Thats using my paddling stroke. With Niels stroke it would be 8W net to raise the blade and 26W total for paddling. This actually sounds reasonable if my assumprions are anywhere near correct and I'll now take my hat off to both Niels and Matt. For what its worth: Niels I'm happy with your ideas - seems to me they give credible answers; and Matt I should never have doubted but I'm happy with your values for kayak power. Many thanks for all the information and discussion. All the best, PeterO *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Sat Apr 30 2011 - 17:59:11 PDT
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